1. Field of the Invention
The present invention relates to a rotational-rate sensor which is capable of detecting a rotational rate.
2. Description of the Related Art
As a conventional rotational-rate sensor, for example, a vibration gyro is known which is described in Japanese Patent Laid-Open No. 11-287658 specification. In this vibration gyro, a vibrator is supported near its node point with a support member which is made up of a U-shaped, fine wire. Both ends of the support member are fixed on a rectangular attachment substrate which is made of glass epoxy or the like. The attachment substrate is fixed to the node-point part in the vibration mode of the attachment substrate which is generated by the vibrator's vibration. Thereby, it is held on a base plate.
However, in such a vibration gyro, a vibration is designed to be separated, using a mechanical filter effect which is produced by lowering the resonance frequency of the whole system. This requires that the vibrator's node point and its vicinity be supported with the U-shaped, fine wire. Such a structure, in which they are supported using the fine wire, becomes extremely complicated. This makes the vibration gyro less reliable, and also makes it extremely weak against an applied impact.